Comment by jeffbee
1 day ago
I worked at a competing white-label email provider in the 90s and even then it seemed obvious that running SMTP on a Sun Enterprise was a mistake. You're not gaining anything from its multiuser single-system scalability. I guess it stands as an early example of pets/cattle debate. My company was firmly on the cattle side.
I was just the Teenage intern responsible for doing the PDU Cabling every time a new rack was added, since nobody on the Network or Software Engineering teams could fit into the crawl spaces without disassembling the entire raised-floor.
I do know that scale-out and scale-up were used for different parts of the stack. The web services were all handled by standard x86 machines running Linux - and were all netbooted in some early orchestration magic, until the day the netboot server died. I think the rationale for the large Sun systems was the amount of Memory that they could hold - so the user name and spammer databases could be held in-memory on each front end, allowing for a quick ACCEPT or DENY on each incoming message - before saving it out to a mailbox via NFS.
Makes sense, there are a lot of reasons why having some "big iron" might have been practical in that era. x86 was not a full contender for many workloads until amd64, and a lot of the shared-nothing software approaches were not really there until later.